Bracket support for rotary disk sander



April 1968 A. KAUFMAN ETAL 3,375,617

BRACKET SUPPORT FOR ROTARY DISK SANDER Filed May 25, 1967 INVENTORS 445527- flap/144M [00/5 Afa/FMAA/ v ATTORNEY United States Patent 3,375 617 BRACKET SUPPORT FOR ROTARY DISK SANDER Albert Kaufman, 11 th Ave., New York, N.Y. 10003, and Louis Kaufman, 111 N.-W00d Lane, Woodmere, NY. 11598 Filed May 25, 1967, Ser. No. 641,302 5 Claims. (Cl. 51-'-170) ABSTRACT OF THE DISCLOSURE The invention concerns a bracket support fora motor driven sanding device which may consist of an independent portable electric motor or the combination of an attachment with a workshop electric drill having'a rotary spindle operated by the motor, and on'the free end of which is detachably mounted a flexible disk of abrasive material. The provision'of the steadying bracket support, of 'U-shape, with at least the base being-of rounded crosssection, and the arms extending-therefrom clamped to the body of the electric motor at an adjustable distance from said base, permits the attainment of a fine degree of control of the angularity of the effective abrading area of the flexible disk as the latter is flxed at the forepart thereof in the course of its translating movement along the surface of the workpiece. The bracket support serves as an effective guide for the rotary abrasive'disk and steadies the latter as the same is guided by a handle extending from the motor body.

This invention relates to a rotary disk surface finishing machine and particularly a disk sanding machine operated by a portable electric motor with a handle extending therefrom. The machine may be constructed specially for this purpose or it may be in the form of an attachment combined with a portable electric drill of the type used extensively in home workshops, in order to diversify the utilitarian purposes of such drills.

It is the object of the present invention to improve disk sanders utilizing abrasive disks of sandpaper, emery fabrics and the like which are adapted to be mounted detachably onto the free end of a rotary spindle, adapted to be driven by a portable electric motor which may be a part of a universal tool for workshop use. Normally, such disk sanders are mounted upon a flexible backing to permit the flexing of the abrasive disk to subject only the forepart of the latter for grinding or polishing action on the workpiece over which the disk is moved in the course of imparting a translating movement to the tool and disk while the latter rotates at high speeds, which speeds may range from 1 800 r.p.m. to 3600 rpm. The use of such a sander requires skill and experience, without which the surface operated upon may be gouged and roughened to the point of ruining the workpiece being smoothed.

It is the object of the present invention to provide an adjustable bracket support for a motor-driven abrasive or smoothing disk which serves to steady the tool in the course of its translating movements and which enables an operator to control the functioning of the flexed abrasive disk with nicety and with maximum safety, while minimizing the risk of faulty operation and damage to the workpiece being smoothed.

It is another object of the invention to provide a steadying bracket support for a motor-driven sander disk which is of simple construction and of low cost, and the mounting of which may be adjusted easily to control the angularity of the flexed portion of the sanding disk relative to the mounting spindle therefor, in order to attain optimum functional results.

It is another object of the invention to provide a ice bracket support which may be mounted easily on existing tools or which may be adapted to new tools by the provision of mounting lugs on the body of the latter.

Other objects and purposes will appear from the detailed description of the invention following hereinafter, taken in conjunction with the accompanying drawing wherein FIG. 1 is a front elevation of a motor-driventool for a sanding disk and an adjustable bracket support therefor, in accordance with the invention;

FIG. 2 is an end view of the bracket support which may be clamped onto the'body of a motor of an electric drill fitted with the attachment for mounting disk sanders; and

FIG. 3 is a perspective view of the adjustable bracket support shown in FIGS. 1 and 2.

As shown in the drawing, the bracket support in accordance with the invention is adapted to be mounted upon the body of the electric motor M forming part of a special sanding tool or universal tool which may be designed for use as an electric drill or other functions. The motor M is fitted with the attachment A mounting a rotary spindle S on the lower free end of which is mounted a sanding disk D of sandpaper or other abrasive material, which is backed by a layer of flexible material R such as foam rubber, and which permits the flexing of the sanding disk at the forepart a so that the abrasive material acts upon the surface being worked upon at only a portion of the sander disk.

A handle H extends transversely from the motor M through which runs an electric cable W for operating the motor. The handle H may assume different forms such as a pistol grip, or closed frame.

Normally, the translating movement imparted to the sander disk, by guiding the tool under the control of the handle H, is affected by the rapid movement of the sander disk so that only an experienced operator is able to control the sander disk to smooth the surface being worked upon without the possibili;y of damaging the surface. The instant invention provides a stabilizing and steadying support for the tool so that the sanding disk may operate reliably and in desirable fashion without danger to the operator or the workpiece.

In the illustrated embodiment, the bracket support assumes the form of a U-shaped cylindrical rod including a base 1 and two upstanding arms 2, 2'. A band B of metal or other material, having a bottom 3, lateral sides 4, 4 and end flanges 5, 5' is adapted to surround the body of the motor and to be clamped thereon by means of threaded bolt 7 and nut 8 extending through openings 6, 6 in the end flanges 5, 5', respectively. The band B may be shaped in conformity to the outlines of the motor body or it may have suflicient flexibility to enable it to be clamped tightly onto the body of the motor. Lateral lugs 10, 10' may be cast integrally on the exterior of the lateral sides 4, 4', respectively. Apertures 11, 11' are provided in the respective lugs 10, 10 through which pass the upwardly extending arms 2, 2 of the U-shaped rest. Thumb-screws 12 and 12' extend laterally into bores 13, 13', respectively, of the lugs and serve to fix the elevation of the arms relative to the body of the motor.

As shown in FIG 1, the adjustable clamping of the arms 2, 2' within the lugs 10, 10 controls the degree of angularity which may be imparted to the forepart of the sanding disk D when the tool rests on the base 1 of the bracket support. An additional element of control may be provided by shifting the band B along the body of the motor to vary the positions of the base 1 rearwardly of the sanding disk D. Thus, in the setting shown in FIG. 1, the angularity is relatively small, whereas if the body of the motor M is raised relative to the base 1 of the bracket support the angularity of the forepart d may be in creased. In all cases the tool is steadied by the bracket support resting on the base 1 as the same is moved with minimum friction along the surface being smoothed by the sanding disk. For this reason the bracket support 1 is of rounded cross-section and preferably is formed of a steel rod of 7 diameter. However, the rod may be formed of plastic material and need not be of cylindrical section as long as the bottom is rounded to permit smooth translating movement of the bracket as the tool is moved back and forth.

While we have described our invention as embodied in a specific form and as operating in a specific manner for purposes of illustration, it should be understood that we do not limit our invention thereto, since various modifications will suggest themselves to those skilled in the art without departing from the spirit of our invention, the scope of which is set forth in the annexed claims.

We claim:

1. In combination with a motor-driven tool having a rotary spindle with a detachably mounted flexible planar disk of abrasive material at the free end thereof,

(a) a hand-supported electric motor for driving said spindle extending therefrom in a transverse direction and fitted with a handle for guiding and manipulating said motor relative to the plane of the flexible disk,

(b) an integral U-shaped steadying bracket support adjustably mounted on said electric motor,

(c) said bracket support having a base of rounded crosssection for slidable contact with a surface being operated upon, and a pair of arms extending upwardly from the opposite ends of said base fixed to the opposite sides of said electric motor at adjustable distances from said base, to permit a fine control of the tilting of the motor as the base of said bracket is slid transversely with minimum frictional resistance along the surface being operated on, and a consequent fine and variable control of the limited area of said disk in the course of operative abrading contact with said surface, conforming to the variable angularity. of the axis of the rotary spindle relative to said surface.

2. A device as set forth in claim 1 including apertured mounting lugs on the opposite sides of said motor for receiving the upwardly extending arms of said bracket support, and means for clamping saidarms to said lugs at a predetermined elevation.

3. A device as set forth in claim 2 wherein said lugs are disposed on the exterior of the sides forming part of a band which is clamped to the body. of the electric motor.

4. A device as set forth in claim 2 wherein said bracket support is of cylindrical section.

5. A device as set forth in claim 3 wherein said band is adjustably mounted on the exterior of the body of the electric motor to vary the position of the base of the bracket rearwardly of the flexible disk.

References Cited UNITED STATES PATENTS 1,945,425 1/1934 Emmons 51-170 X 2,114,966 4/1938 Myers 51- -177 2,229,745 1/ 1941 Kneisley 51-170 2,242,229 5/ 1941 Burleigh 51-177 2,507,052 5/ 1950 Robinson 51-177 2,603,919 7/1952 Robinson 51-177 LESTER M. SWINGLE, Primary Examiner. 

